Applying negative pressure to a physiological area such as a wound, for example, enhances drainage of fluids or exudate from the wound and promotes tissue growth and wound healing. This method of healing (known as “cupping”) was exercised since the times of ancient Greek physicians until the 19th century. Applying negative pressure to other physiological areas such as burn, for example, is also beneficial even when there is no draining.
There are also other situations in which it may be desired to apply a vacuum or suctioning to a particular volume, such as to prevent or minimize contamination of the pump drive unit, for example when removing flowable contaminated, toxic or hazardous materials from a particular location.
By way of general background, a number of systems and methods have been developed for providing suctioning and/or for treatment of wounds, for example as disclosed in the following publications, which also include a number of examples of pumps and venting valves, the contents of which are incorporated herein in their entirety: WO96/05873, WO 97/18007, WO 03/016719 (US 2004/028756, GB 2,378,734), U.S. Pat. No. 6,648,862; U.S. Pat. No. 5,645,081; GB 2,307,180 (EP 0865304); U.S. Pat. No. 4,739,791; WO 03/030966; US2004/0064132; WO 2006/052745; WO 03/057070; US 2005/192548; WO 2007/013049; WO 2007/013064, U.S. Pat. No. 5,370,610, U.S. Pat. No. 5,662,599, U.S. Pat. No. 6,471,982, U.S. Pat. No. 5,636,643, U.S. Pat. No. 7,128,735, U.S. Pat. No. 6,824,533, U.S. Pat. No. 6,562,013, U.S. Pat. No. 4,447,226, U.S. Pat. No. 4,611,627, U.S. Pat. No. 1,599,899, WO 00/02016, EP 156211, DE 2401643, U.S. Pat. No. 6,071,267, US 2005/004534, US 2004/039243, US 2003/014022, U.S. Pat. No. 3,416,461, U.S. Pat. No. 5,419,687, US 2001/029956, US 2001/029956, DE 10215896, U.S. Pat. No. 6,042,560, U.S. Pat. No. 4,930,997, U.S. Pat. No. 4,661,093, U.S. Pat. No. 5,776,119, US 2004/059284, US 2003/097100, US 2003/040687, US 2003/050594, WO 2004/037334.